With every case from years ago there should be lessons learned.

President Trump talks about extreme vetting, and we actually do have extreme vetting when it comes to refugee resettlement. Refugee resettlement is the most thorough, cumbersome, multilayered vetting system we have for the admission of anyone to the country.

I think that the potential for homegrown terrorist attacks is something that we have to be very concerned about, because, in many respects, it's harder to detect when you have an independent actor who may be living in our midst, in our own communities.

Politics, in my judgment, has become not just the means to a policy ends, but it's become the end itself. Politics has become the sport that we all watch, and we all pay attention to.

We are very definitely in a new phase in the global terrorist threat where the so-called lone wolf could strike at any moment.

If you build - if you spend billions of taxpayer dollars to build a wall over, let's say, a mountain, if you build a 10-foot wall over a 10,000-foot mountain, and someone is determined to climb the 10,000-foot mountain, they're not going to be deterred by the 10-foot wall. It's a matter of common sense.

With every case from years ago there should be lessons learned.